He came up with iconic tire tread designs (Specialized Ground Control, WTB Velociraptor) that are still rolling down trails today. Charlie built the earliest aluminum mountain bikes you’ll ever find, and designed them with sloping top tubes and reinforcement gussets years before anyone else figured out that those were smart frame elements. Roller-cam brakes were Charlie’s idea, and they woke up the bike industry to the fact that cantilevers didn’t stop mountain bikes very well. 135mm rear hub width (which reduced wheel dish and spoke breakage)? Charlie. Grease Guard cartridge bearings that could be repacked with grease without removal? Charlie. Tubular (instead of flat plate) fork crowns? Charlie. Dirt drop handlebars? Charlie.